Windows Loader: Unsupported Partition Table

Hello! I recently bought a new hard drive to install my copy of windows 7 ultimate on. Once I installed the OS, and ran the older loaders, I got an error message saying that a message was sent to the error log..of some sort. After downloading and installing the newest version, I cant even install the loader - it says Status: Unsupported partition table". Im assuming thats what's holding me up. How can I resolve this?

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Staff Member

Q. The loaders status says "Unsupported partition table", why is this?
A. You're either using GPT on a UEFI motherboard or you've got a locked OEM partition. Both problems can be fixed by fully formatting your entire hard drive.
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# 4 - UEFI motherboards
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The loader doesn't work when the systems using GPT via UEFI. The workaround is to pre-format your hard drive so that it uses MBR instead.
From your BIOS select to boot the Windows DVD without UEFI, go to the repair options, select command prompt and then enter this:
diskpart
list disk
select disk 0
clean
convert mbr
create partition primary
select partition 1
format fs=ntfs quick
Boot the Windows DVD the same way you did the first time and then continue with the installation of Windows. Once complete you can install the loader.

So you either have an OEM partition that the loader can't gain write access to or you're using GPT via UEFI.

Q. The loaders status says "Unsupported partition table", why is this?
A. You're either using GPT on a UEFI motherboard or you've got a locked OEM partition. Both problems can be fixed by fully formatting your entire hard drive.
##########################################################################
# 4 - UEFI motherboards
##########################################################################
The loader doesn't work when the systems using GPT via UEFI. The workaround is to pre-format your hard drive so that it uses MBR instead.
From your BIOS select to boot the Windows DVD without UEFI, go to the repair options, select command prompt and then enter this:
diskpart
list disk
select disk 0
clean
convert mbr
create partition primary
select partition 1
format fs=ntfs quick
Boot the Windows DVD the same way you did the first time and then continue with the installation of Windows. Once complete you can install the loader.

So you either have an OEM partition that the loader can't gain write access to or you're using GPT via UEFI.

Click to expand...

That's it! I did use the GPT via UEFI when I originally booted and installed windows. I suppose Ill just reinstall..again! Thank you very much. Was beginning to get concerned for those on here that just liked to accuse me of being ignorant rather than helping.

This is not the smartest thing to do. As the user has stuff installed on there.

How about this:

- verify if it really is MBR
- If Windows partition is C - copy bootmgr to it and apply a bootloader to it (bootsect.exe) as well as make it active (diskpart)
- delete crazy "recovery" partitions to be left with C and D
- sort partition appearance in partition table with ??? tool

cross fingers and hope for Windows to boot and try to activate again

If someone is able to test and develop such a method - please do and post exact instructions.

I have a 3TB hard disk and Windows can only use the full 3TB if the partition type is GPT.
My drive had to be formated with MBR partition type in order to Loader works properly but now I have only a 2TB partition and 1TB that I cannot use. The Loader will continue to work even if I convert my partition to GPT? What do you guys think about it?

Staff Member

It won't as the loader doesn't fully support GPT drives unfortunately. You're one of the few that are actually using a large drive so the loader may not be the best solution for you. Maybe a BIOS mod or you could try nononsence's program in the MDL projects section.

It won't as the loader doesn't fully support GPT drives unfortunately. You're one of the few that are actually using a large drive so the loader may not be the best solution for you. Maybe a BIOS mod or you could try nononsence's program in the MDL projects section.

Click to expand...

Hi Daz, I'm not too comfortable with the idea of modding my BIOS. I just updated to a P8Z77-V Pro Asus motherboard and Ivy Bridge i5 processor. Everything would be fine except I got a 3TB WD drive - which in retrospect has been a big pain in the ass.

So, do you expect to support UEFI and GPT drives eventually? Drives are getting larger and 3TB and larger drives will become more common by the end of this year. Please let me know your thoughts, thanks!

Staff Member

Hi Daz, I'm not too comfortable with the idea of modding my BIOS. I just updated to a P8Z77-V Pro Asus motherboard and Ivy Bridge i5 processor. Everything would be fine except I got a 3TB WD drive - which in retrospect has been a big pain in the ass.

So, do you expect to support UEFI and GPT drives eventually? Drives are getting larger and 3TB and larger drives will become more common by the end of this year. Please let me know your thoughts, thanks!